High performance polymers are a class of polymers that exhibit good temperature and chemical resistance. These materials have been examined for use in a variety of applications due to their excellent physical characteristics and low weight. For instance, replacement of metal components with high performance polymers can provide lower weight, lower cost products (e.g., piping) with physical characteristics that meet or exceed those formed of traditional materials.
Polyarylene sulfides are high-performance polymers that have often been blended with other components to provide thermoplastic compositions having the excellent characteristics of the high performance polymer in conjunction with other desirable characteristics. For example, elastomeric impact modifiers have been combined with polyarylene sulfides for improvement of the physical properties of thermoplastic compositions.
Unfortunately, elastomeric polymers generally considered useful for impact modification are expensive, adding significantly to the costs of the thermoplastic compositions. Moreover, typical impact modification polymers are not compatible with polyarylene sulfides and phase separation has been a problem in forming compositions of the two. Attempts have been made to improve formation of the compositions, for instance through the utilization of compatibilizers. However, even upon such modifications, compositions including polyarylene sulfides in combination with impact modifying polymers still fail to provide product performance as desired, particularly in applications that require resistance to hydrocarbon absorption such as oil and gas applications.
Polyolefin compositions have been formed in the past by uniformly mixing an elastic component with a thermoplastic polyolefin such that the elastomer is intimately and uniformly dispersed as a discrete or co-continuous phase within a continuous phase of the polyolefin. Vulcanization of the composite has been utilized to crosslink the components and further improve dispersion. When vulcanization is carried out in conjunction with combination of the various polymeric components it is termed dynamic vulcanization.
What are needed in the art are lower cost polyarylene sulfide-based thermoplastic compositions that can exhibit desirable characteristics.